A discharge lamp device such as a headlamp including a discharge lamp, like a high intensity discharge (HID) lamp, as a light source uses a power-supply device (lighting circuit module) to control lighting of a discharge lamp.
Such a power-supply device includes: a lighting circuit (power circuit) for lighting a discharge lamp; and a circuit case (housing) that houses the lighting circuit. The power-supply device is often fixed to the outside of a lamp housing in a discharge lamp device (see Japanese Unexamined Patent Application Publication No. 2009-170359, for instance).
In this case, to electrically connect the lighting circuit in the circuit case and the discharge lamp in the lamp housing, a through hole that communicates with both the lamp housing and the circuit case is formed in each of the lamp housing and the circuit case. Moreover, a connector terminal that projects toward the lamp housing to face the through hole is connected to a circuit board of the lighting circuit. Furthermore, an input/output cable line (harness) is led out from the lamp housing, and is interested in the through holes of the lamp housing and the circuit case and connected to the connector terminal of the circuit board.